Time to Get Busy

1. Time to Get Busy While We Wait for Everyone

2. ASTR-1010Planetary Astronomy Day 4

3. Course Announcements • The first two 1st Quarter Night Observing sessions are: Tues Sept 14 and Wed. Sept. 15 @ 7:30pm

4. HOMEWORK Read Chapter 2 Homework Chapter 2: Due Thursday Sept. 16 Beginning with chapter 2, you better read the text and THINK before you blindly answer questions.

5. Monument Valley, Utah

6. Anyone recognize any shapes here?

7. Star Names Betelgeuse Aldebaran Rigel SIRIUS

8. Pleiades Great Orion Nebula Using Orion in to find other objects Aldebaran Sirius

9. Pleiades Seven Sisters Subaru

10. Consider the dome of the sky over our heads…. mixing bowl

11. Consider the dome of the sky over our heads…. inverted mixing bowl ….

12. Imagining a spinning Celestial Sphere surrounding Earth aids in thinking about the position and motion of the sky

13. Animation!

14. Celestial Sphere Rotation Celestial Sphere Rotation Star B Star B 2 2 Star A Star A 1 2 2 1 North Star Celestial Sphere Celestial Sphere 3 3 1 1 4 4 3 3 Horizon Earth’s Equator 4 4 Celestial Sphere Rotation Celestial Sphere Rotation Figure 1 Figure 2

15. Celestial Sphere Rotation Star B 2 Star A 1 2 Celestial Sphere Celestial Sphere 3 1 4 3 Horizon 4 Celestial Sphere Rotation Figure 2 Is the horizon shown a real physical horizon, or an imaginary plane that extends from the observer and Earth out to the stars? Can the observer shown see an object located below the horizon? Is there a star that is in an unobservable position? When a star travels from being below the observer’s horizon to being above the observer’s horizon, is that star rising or setting?

16. Lecture Tutorial pg. 1Position • Work with a partner! • Read the instructions and questions carefully. • Discuss the concepts and your answers with one another. Take time to understand it now!!!! • Come to a consensus answer you both agree on and write complete thoughts into your LT. • If you get stuck or are not sure of your answer, ask another group.

18. Celestial Sphere Rotation Star B 2 Star A 1 2 Celestial Sphere Celestial Sphere 3 1 4 3 Horizon 4 Celestial Sphere Rotation Figure 2 In what direction is the observer facing? A)toward the South B)toward the North C)toward the East D)toward the West

19. Imagine that from your current location you observe a star rising directly in the east. When this star reaches its highest position above the horizon, where will it be? high in the northern sky high in the southern sky high in the western sky directly overhead

20. Where would the observer look to see the star indicated by the arrow? Celestial Sphere Rotation Star B 2 Star A 1 2 Celestial Sphere Celestial Sphere 3 1 4 3 Horizon 4 Celestial Sphere Rotation Figure 2 High in the Northeast High in the Southeast High in the Northwest High in the Southwest

21. What you see at night also depends on where you are Cerro Tololo, Chile

22. What you see at night also depends on where you are Mauna Kea, Hawai’i

23. Celestial Sphere Rotation Star B 2 Star A 1 2 Celestial Sphere Celestial Sphere 3 1 4 3 Horizon 4 Celestial Sphere Rotation Figure 2 Nightly Motion of the Stars

24. Nightly Motion of the Stars • For stars (the Moon and planets) that appear in the southern sky: Stars first rise near the eastern horizon, move upward and toward the south, and then move down and set near the western horizon.

25. Looking North: Circumpolar Stars • Circumpolar stars seem to move counter-clockwise around the stationary North Star. • These constellations and stars are visible any night of the year in the NORTHERN sky because they never rise or set! • Examples: Ursa Major, Ursa Minor, Draco, Cepheus, and Cassiopeia

26. ClassAction Stuff • Big Dipper Clock

27. HomeworkRanking Tasks – MotionExampleOthers due Tuesday, Sept. 14 at class time

28. Why does the sky change during the course of a night? The Earth rotates about its’ polar axis so the stars make circles around the celestial pole over the course of a night

29. Why does the sky change with your location? As you move away from the pole your horizon moves with you but the locations of the celestial poles and celestial equator remains the same

30. Why does the sky change over the course of a year? As we orbit the sun the direction opposite the sun changes and we only see the stars when the sun is not up

31. So, the Earth moves in two ways that affect what we see Orbital motion around the sun causes seasonal changes in the constellations Rotational motion around the polar axis causes changes over the course of the night